Although peer relations are considered to make significant contributions to social and emotional development and poor peer relations have been shown to be highly predictive of later adult maladjustment, the study of the peer relations of ADDH and conduct disorder children has been almost completely ignored. The objective of the proposed research is to use the currently available knowledge base on peer relations of normal children to design and to implement an observational coding scheme for evaluating the peer relations of ADDH and conduct disorder children. Toward this aim, a temporal model of relationship development has been proposed. This model serves as the basis for two complementary observational coding systems that will be used to specify the social context in which peer interactions are occurring as well as the specific behaviors of the children. The design of the proposed research includes three experimental groups--ADDH, conduct disorder, and mixed ADDH/conduct disorder--and two comparison groups--psychiatric control and normal control. A minimum of eight and a maximum of sixteen children aged 6-12 will be included in each group, and their peer interactions will be observed in both a classroom and a playground setting for a total of four to six hours. Rather than simply documenting that ADDH and conduct disorder children have deficits in their peer relations, a plan of analysis is proposed for use with the event sequential data from this study that will allow for specifying where in the temporal process of relationship development these children are experiencing difficulties. In the short term, these findings should have immediate implications for the improvement of behavioral interventions and social skills training programs with these two clinical populations. Over the long term, the proposed research is designed to serve as a basis for future investigation of medication effects on the peer relations of ADDH and conduct disorder children, developmental changes in behaviorally disturbed children's peer relations, and the contribution of the family system to these children's poor peer relations.